Method for making pad-covers.



PATENTED NOV. 26, 1907.

G. P. STEWART.

METHOD FOR MAKING PAD COVERS.

APPLICATION FILED APR. 17, 1907.

2 SHEETS-SHEET 1 Nol 8.7l,966. PATBNTED NOV. 26, 1907.

G. F. STEWART.

METHOD FOR MAKING PAD COVERS.

APPLIOATION FILED APR. 17. 1907.

2 SHEETS-SHEET 2,

GEORGE F. STEWART, OF LYNN, MASSACHUSETTS, ASSIGNOR TO MANUFACTURERS MACHINE' COMPANY, OF MONTOLAIR JERSEY.

, NEW JERSEY, A CORPORATION OF' NEW METHOD FOR. MAKING PAD-COVERS.

Specification of Letters Patent.

Patented Nov. 26, 1 907.

Original application filed July 13. 1906. Serial No'. 326.147. Divided and this application filed April 17. 1907. Serial No. 368.649.

To all whom it may concern.'

Be it known that I, GEORGE F. STEWART, a citi-Zen of the United States, residing at Lynn, in the county of Essex, Sta te of Massachusetts, have invented an Improvement. in Methods for Making Pad-Covers, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

The invention to be hereinafter described relates to a method of making covers for bui'ling machine pads used in treating boots and shoes and' is a division of application serially numbered 326,147, filed July 13, 1906.

As well understood by those skilled in the art, bulling machines of the Naumkeaff type are provided with builing pads of su stantially disk-like form, usually inflatable to give the desired rounded and resilient surface or working iace. `Such pads are usually provided with detachable covers, preferably formed of some abradant material suitable for acting upon the work and are mounted upon spindles driven at high speeds. Owing to wear and changing conditions of the work to be treated, it becomes necessary'irom time to time to change the covers upon the pads. 1n providing detachable covers for the pad-s oit such machines it has been proposed to form the cover with a substantially ilat circular unmolded central portion and a lmarginal portion molded or turned into a position substantially parallel with the central 'flat portion. Owing to the ilat unmolded character of the working facc of such a cover, however, it could be applied to the pad only when the latter was in a lattcned or deflated condition. 1t has also been proposed to mold thecntire pad cover, including the working face and marginal portion, to a shape substantially the same as such parts are to have during working conditions, that is, to the shape the cover should have when upon the intlated pad. lirst ol' these proposed pad covers, the workinglace ol the blank l'rom which the cover is formed, is not materially stretched, but remains substantially in the original condition ol' the material otl which the blank is composed, while the .marginal portion is, by a moldingoperation, turned in over the working face to produce a substantially smooth inturned tlange or attaching portion, the i'old at the liunction ol' said attaching portionwith ln the method oll forming the the periphery of the working face being molded to circular form to correspond with the periphery of the pad upon which the cover is used. This result is attained by forcing the marginal portions of the blank, while 1n a tem ered condition and yieldingly held by suitab e clamps, directly inward over a flat tormer applied to and corresponding in size and shape with the Working face of the pad cover.

In order to produce a pad cover in accordance with the second of the proposed forms, a flat blank or piece of suitable material, preferably theemery cloth of commerce, is yieldingly secured around its marginal portion and the middle unclamped portion is then subjected to lateral pressure, which stretches and bulges the material and at the same time causes the marginal clam ed portion to slip between the clamps an to contract or draw in towards the center of the blank, which, at the end of this operation, is of smaller' size at its peri her than the original blank, but is strctciied aterally, so as to provide fullness within the-contracted periphery. The stretched or full portion is then extended or stretched radially outward, so that the material within the clamped peri )hery and which forms the wonking race of the cover, becomes extended to a larger diameter than the clamped periphery, the stretching and extending being performed preferably as two consecutive operations. Thus, in both of the proposed methods of forming pad covers of the character hereinbefore mentioned., the marginal portion ol the blank was allowed to slip or draw through the holding moans without.' positivi` or compensating control ot the marginal movement during the molding action, and to secure the full molded form to the work` ing face of the cover in the second of the proposed methods, Such i'ace portion, already 1n a laterally stretched condition, was given an additional outward radial stretching.

The method of making pad covers constituting the present invention ditl'ers essentially from each ol these not only in the acts or series of acts and the sequence ol` their performance upon the blank, but .in the principles involved, whereby there is produced an initially strong pad cover vof the desired molded form, bot h as to faceandmarginal portion, easily pla-ced upon orLremoved from a pad uithout deformation of either,

referred and wherein the molding strains or other acts have been so disposed and controlled as to permit the component elements of the cover material to remain in their initially durable relation to each other. The method of the present invention distinguishes in principle from each of those hereinbefore to, in that while the blank is held at its marginal portion and subjected at its central portion to a molding pressure transverse to the plane of the blank, the said marginal portion is held and given a controlled compensating movement to counteract any tendency to unequal stretching, economize in amount of material used, and to carry the marginal portion about the molding element proportional to the molding stretch imparted to the blank. This and other characteristics ol the present method, as distinguished from those heretofore proposed, will more cle-arly hereinafter appear, as the presentmethod is more fully developed in connection lwith the accompanying drawings, which are illustrative of one embodiment of means adapted for carrying it into effect.

In the drawings-Figure l is a sectional elevation illustrating the agencies, as embodied intio'ne form of appropriate mechanical device, that act upon the blank in carrying out the present method, Fig. 2 is an unv derneath plan view of the top portion of Fig.

l., showing the agencies for imparting con- A, trollable cpinpensating radial movement to vto 'tion thereof, may be in the'form of a series ofy which, when the the marginal portion of the blank to carry it about the molding element Fig. 3 is a diagrammatic view showing the agencies, in the "mechanical devices-selected for illustration thereof, in the condition they assume with relation to the blank during the iirst portion of the molding o eration 5 Fig. l is a view similar to that of Fig. 3 showing the agencies in the condition assumed near the end of the molding operation; Fig. 5 is a plan view of the preferred form of blank which may be emtp eyed; Fig. 6 is a top plan view of the pa cover completed; Fig. 7 is a side View of the com leted cover.

In or er to produce a molded pad cover for buffing machines in accordance with the present invention, a blank a, Fig. 5, of suitable size and shape, preferably though not necessarily of somewhat elliptical form, has its marginal portions secured between clamping members, which in the selected illustrajaws 1 and 2, arranged upon a head A, sub- Stantially as shown, said jaws being provided with serrated or roughened faces to securely and positively clamp and`hold, the blank. The clamping members may be caused to engage the Amargin of the blank and hold it during the'` nol ing operation by any suitable means, that shown being a ring or carrier 3, blank has been placed in -holding the marginal portion of t arnese position either by hand or by the positioning devices 4,5, as fully set forth in the application hereinbefore referred to, is caused to move upward and engage the jaws 2, closing them firmly upon the marginal portion of the blank. The said blank with its marginal portion thus clamped and positively held, then has its middle portion pressed in a direction transverse to its plane, preferably by a plunger or molding element 6, having a convex end conforming substantially with the surface contour desired for the working` face' of the cover. As the middle portion of the blank is being thus molded to shape, the clamping members, while still ositively lie blank, are given a controlled compensating movenient, in the present instance, radially inward or towards each other, to carry the marginal portion of the blank about the molding element or plunger head and preferably into a rec-ess extending about the plunger, thus completing the molded character 'of the working face, and forming an encircling channel c with outer ilaring and inner walls b, d. controlled compensating movement of the clamping 'members may be secured by any appropriate means, as, for instance, that set forth` and fully descri l)ed in my pending application referred toan. best herein shown by Figs. l and 2, wherein the clamping members are each provided witha pin or stud 7, projecting into inclined or eccentrically arranged grooves 8, movable with or formed in a ring 9, which given a .partial rotation with respect to head A, at

appropriate times by an actuator l0, connected to an car il ,projecting from said ring able means. i

Pad covers are usually, though not necessarily, made of emerj,l coth, and when such material is empiou cd it is found to stretch unevenll,VV during the molding operation, owing to the fact that some of the threads thereof 5 ield more than others. This tendency to unevenl'y stretch is, in the present method, practically nullified by the described manncr of giving to the marginal portion of the blank a controlled compensating movement, regardless of the particular shape or contour desired for the resulting product, because, by holding the marginal portion of the blank without slip and controlling the movement thereof all portions of the blank are caused to stretch uniformly, only a narrow marginal portion need beheld, sutlicient to produce the flaring outer wall or peripheral portion, thus resulting in economi.' of material as compared with prior methods of production, and all liabilityof injury to the abrading material on the part of the blank thus positively and controllabl' held is avoided, as will be obvious to one familiar with the art. To further com ensate for uneven stretching an elliptical term of blank maj.' be used, as indicated in Fig. .5, though obviously the present invention is in no sense dependent thereon, although when used a dill'erential com pensating movement given the clamping members, so that the marginal portion ot' such elliptical blank at or near the major axis thereof will be given a controlled movement greater than that at or near the minor axis during the molding operation. in the devices selected for illustrating the agencies that act upon the blank, this dill'erential comensating movement of the clani ping memliers is secured by giving appropriate varia- 'tion of inclination to the grooves S, those adjacent the major axis of the eiipse being ,more inclined with reference to the perimeter of ring 9, than those adjacent the minor axis, as will be readily understood by those skilled in the art.

The present method contemplates as a part thereof a molding action upon the marginal ortion ol the blank such that the complete( cover, molded to the shape it must assume when in position upon the inflated pad, shall'have an ou twardiy llaring and strengthening peripheral edge to the end that it maj? be more readily applied to and` conform with the pad without deformation and maintain its molded character. This strengthened larine' eliaractin'istie is secured by molding ribs, eorrnga'tions, or pinnacles f,f transversely of the outer llaring wall and such transverse ribs, corrugations, or pinnacles areappropriatefy formed during the operation of molding the cover by circumferentially contracting the outer flaring wall while positively holding it at intervals between radially movable elements. As one means ol" securing this end the clamping memlier's or jaws l, Q, in the selected 1llustration, are so disposed that when in )osition to receive between them the flat lank, the jaws constituting one clamping member are spaced a short distance circumiercntiallv from the next adjacent members, the ends ol the jaws being slightljT beveled or chambered olil on their vertical edges, as at 12, Fig. 2, so that as the clamping members are vmoved radially inward, positively holding the marginal portion of the blank, thejy will produce the ribs, corrugations, pinnaclcs between the adjacent clamping members, while maintaining' the marginal portion between the jaws in smooth haring condition.

While the method thus far pointed out and described has been lound advantageous and of distinct advantage over any of the prior methods known to me l'or producing butling pad covers molded lo the vform` they are to ave onthc inflated or distended pad, l. have found improved results secured inthe treatment ot some. materials by givmg to the lrelatively moving the blank and molding element or plunger while in molding contact and during such action maintaining the molding elenrcn t at the desired temperature., ln the devices illustrating the operation ol the present invention the molding element or plunger (j is provided with aheatingchambcr 13, connecting by a suitable passage l=t with a source of heat supply, and such molding element may be given a partial turningl or oscillating movement back and forth about its longitudinal axis, as lully explained in the said pending application and as will be readily understood by those skilled in the art i withoutfurther elucidation.

In molding the pad cover in accordance with the present method the blank may, il desired, be moistened on the side thercol' to be subjected to the molding pressure, the

moistened portion preferably being conlined to 'parts well within the margin. Sincc'a heated molding element may be employed it is apparent that the moisture on the blank will be converted into steam or vapor between the molding element or plunger and the face olt the blank against which it acts, and, having no escape, will pass through the material ol the blank, imparting thereto a condition ol pliability most suitable for molding purposes without at the same time injuriouslywctting or injuring the abradingsur- Prclerably, the lower side of the blank is thus moistened, and the moldingprcssure applied l'roin beneath, as shown.

The llat blank having been placed in and. held by theclamping members; its working face is subjected to the molding j'n'essure ,1 its marginal portion is moved by .a controlled compensating action to carry the marginal portion about the molding element; the ribs, corrugations, or pinnacles are formed and 'molded at. intervals upon the flaring continuous marginal portion constituting the outer wall ol' the encircling groove produced in the blank by the compensating movemeut ol the clamping members, and the molding action may be facilitated byheat, moisture and attrition or any one or two ol' them, if desired. 'lhc 'flaring marginal and reinforced portion is released by the clamping members, and the molding element or plunger is withdrawn, leaving the now molded cover complete and in the condition it would assume upon an inllated or distended pad.` l

The present invention relates solely to the process or method ol making pad covers, and is in no way dependent upon or limited to any specific appliances lor carrying out the method, it being obvious that the herein described method may bc performed by other one skilled in the art, that it is quite distinct from either of those hereinbefore referred to as constituting the prior `attempts to produce bufling pad covers. It differs from each of these proposed methods not only in the particulars hereinbefore noted, but in the further fact that by the present method 'the marginal portion of the blank is gilven a reinforced molded and strengthening character readily adapting it for application to a pad,

that it imparts to' the cover transverse ribs, corrugations or pinnacles during the molding operation and subjects the blanks to no strain calculated to destroy or otherwise injure or disturb the component elements Which compose the blank, thereby preserving its initial strength 'and abrading character.

In view of the inherent principle involved by the present method, it is unnecessaryto Wet the margin of the blank to insure the proper set of the molded margin, since by ridging or c-orrugating the same the margin is strengthened and held from deformation; by ridging-or corrugating the margin to provide it with pinnacles, there is provided a capacity for elastic action in the application of the cover to the pad; by flaring the margin and molding it in the process of manufacture,

the application of the cover to the pad is facilitated. It will be apparent to one skilled in the art that by positively control'- ling the marginal movement of the blank during the molding thereof, a cover is obtained of the proper' form; and by moving or feeding the margin radially inward during .the stretching incidental to the molding action and proportional thereto, deformation is prevented; that if the cover be subjected to a so-callo'd ironing action during the molding operation, the proper shaping thereof is facilitated; and that by heating the blank While the same is being molded, a more read.

ily molded form is produced.

Claims.

1. The method of molding bufling ad covers Which consists in ap lying a mol( ing pressure to the body of a ilank within the marginal portion thereof and controllably moving the marginal portion during thc actionof a molding pressure.

2. The method of molding bufling pad covers which consists in ositively holding the marginal portion of a lilank against slip, applying a molding force to the body of the `blank Within the margin, an

blank Within `the marginal portion, and giving to the marginal portion a controlled compensating movement while the molding force is acting on the body of the blank.

3. The method of molding bufiing Sad covers which consists in ositively hol ing the marginal portion of a llilank against slip, applying a molding force to a portion of the blank within the margin, and carrying the marginal portion of the blank radially inward about the molding element by a con# trolled compensating movement during the ,action of a molding force.

4. The method of molding1 buffing (pad l ing covers which consists in ositively ho the marginal portion of a blank against slip, ap'pving a molding force to a ortion of the dJ controllably moving te marginal portion-differentially While the molding force is acting on the blank. A

5. The method of molding buff'ing pad covers which oonsists in holding the marginal portion of a Ablank against slip, applying a molding force and attritive action to a portion of the blank Within the margin, and giving to the marginal portion a controlled coin'- pensating movement radially inwai l 6; The method of molding b-uffing pad covers Which consists in holding the marginal portion of a blank to be molded, ap lying a molding force to'a portion of the blanli Within `the margin, andl molding on the marginal -portion transverse ribs or corrugations.

, 7. The method of molding buffing pad covers which consists in holding the marginal portion of a blank against sli'p at intervals, applying to a portion of the blank Within the margin a molding pressure in a direction` transverse to its plane, and giving to the held portions of the margin a controlled compensating movement radially inward and producing on the margin of the blank between the held portions transverse ribs, corrugations; or pinnacles.

i 8. The methodV of molding-buifing (pad l ing covers which consists in applying a mo force to the body of a blank Within the marginal portion thereof; and forcing moisture through the material of the blank during the molding action.

9. The method of molding buiiing pad covers which consists in moistening that surface of the blank which is to be subjected to molding pressure, applying heat and molding pressure to the body of the blank and forcing the moisture through the texture of the blank.

In testimony whereof, I have signed my name to this specilication, in the presence of two subscribing Witnesses.

GEORGE F. STEWART. VV-itnesses SIDNEY F. SMiTH, REDFIELD H. ALLEN.V 

